Apparatus for condensing nitric acid.



PATENTED 00T. 4, 1904.

0. GUTTMANN. t APPARATUS PDR GONDBNSING NITRIG ACID.

APPLIUATION FILED DEOZB, 1901.

No MODEL.'

UNITED STATES Patented October 4, 1904.

PATENT OFFICE.

lAFPAFRTUS FOR CONDENSING NITRIC ACID.

SPECIFICATION forming part of Letters Patent No. 771,629, dated October4, 1904. Application tiled December 26, 1901. Serial No. 87,351. (Nomodel.)

T0 all whom it mag/concern:

Be it known that I, OSCAR GUTTMANN, a subject of the King of GreatBritain and Ireland, residing at 12 Mark Lane, in the city of London,England, have invented a new and useful Apparatus for Condensing NitricAcid, of which the following is a specification.

My invention relates to an apparatus for condensing nitric acid, and hasfor its object the condensation of nitric acid from the gaseous into theliquid state in such manner that a liquid nitric acid is obtainedcomparatively free from impuritiesf rl"he apparatus as hereinafterdescribed is of simple construction and at the same time more eliicientand durable than the condensing apparatus heretofore employed for suchpurpose.

My in vention consists in the combination of the usual condensing pipesor vessels with connecting units each provided with an inlet and' anoutlet for the gases and an exit at the bottom for the condensed liquidand also with a common receiving-channel, the said connecting unitsforming a cover for the receivingchannel.

It is well known that in order to obtain liquid nitric acidcomparatively free from impurities it is necessary to remove thecondensed liquid nitric acid as rapidly as possible from contact withthe uncondensed nitrous vapors and other gases which arise duringdistillation, since otherwise the vapors and gases by prolonged contactwith the condensed liquid acid become absorbed or dissolved therein,thus resulting in the production of a liquid nitric acid containingnitrous acid and other undesirable impurities'. It is also well knownthat in the manufacture of nitric acid it is advantageous to condensethe .acid from the gaseous to the liquid state at as high a temperatureas possible, so as to avoid as far as possible the presence of suchundesirable nitrous acid and other impurities in the condensed acid,because such nitrous acid and other impurities are less soluble and lessabsorbent in the liquid acid at a higher temperature of condensationthan at a lower one. If, moreover, a water-white liquid-nitric acid isrequired, it is advisable to condense the liquid acid at as high atemperature as possible, so that when air is afterward blown through thewarm liquid acid the undesirable nitrous acid and other impurities whichproduce discoloration may be the more readily and rapidly removed.

The condensing apparatus usually employed inthe manufacture of nitricacid consists of a number of condensing vessels or pipes, and for thepurpose of quickly removing the condensed acid out of contact with theuncondensed gases these vessels or pipes are sometimes connected toso-called chamber-pipes of stoneware or like material. Suchchamber-pipes are pipes divided into a number of small compartments bypartitions rigidly built in them at right angles, and these chambers areconnected to each other by U-tubes. These chamberpipes are diicult tomake. They must of necessity be of considerable length and must berigidly connected to the condensing vessels or pipes in order to fornithe com plete condensing apparatus. Both on account of these partitionsand U-tubes, as also of the rigid connections, the chamberpipes aresubjected to unequal expansion and contraction under the combinedinfluence of the hot condensed acid and the uncondensed acid vapors intheir interior and of the colder exterior air. This irregular expansionand contraction frequently causes fracture of the chamber-pipes,resulting in great inconvenience and breakdown of the work and also lossof condensed acid, besides the expense for replacing the brokenchamber-pipes. It is alsol obvious that if a higher temperature ofcondensation is employed the interruption in working, loss of acid, andexpenses involved will be more frequent in consequence of the greaterexpansion and contraction through the greater diierence between thehigher temperature in the interior of the chamber-pipe and thetemperature of the external air.

My improved condensing apparatus is of such construction that thecondensed acid is immediately removed from contact with the uncondensedproducts, the temperature of condensation being at the same time soregulated and the whole operation so conducted that fracture or crackingof the component parts of the apparatus from the causes above mentionedis avoided.

The annexed drawings illustrate the inanner in which my invention can becarried into effect, like letters referring to like parts throughout thevarious figures.

Figure l is a longitudinal section of my improved condensing' apparatus,certain parts being shown in elevation. Fig. Q is a crosssection takenon the line fr z/ of Fig'. 1. Fig'. 3 is an elevation, partly insection, of a portion of the end of the apparatus, showing theconnection of the collecting vessel for the condensed acid with overflowand outlet pipe of the receiving-channel of the condensing apparatus.Figs. l and 5 are cross-sections of modified forms of the apparatus.

My improved condensing apparatus consists of a number of condensingvessels or pipes of ordinary form, which being' well known are not shownin the drawings, each two of which are jointed to a connecting unit ABC.rIhe units for this purpose have at the top inlet and outletsocket-pipes D and E for the passage of the acid gases or vapors to becondensed, and at the bottom a short exit-pipe F for the discharge ofliquid nitric acid condensed in the said vessels or pipes. '.lheseconnecting units may be of any suitable crosssection-f'or example, ofcylindrical section, as in Fig. 2. The connection between thecondensing' vessel or pipe at the outlet of any connecting unit and thecondensing vessel or pipe at the inlet of another connecting' unit iseffected by pipe bends in the usual manner. y

The above-described connecting units A B C rest on the top flanges ofthe trough-shaped receiving-channel into which runs the acid condensedin the condensing vessels or pipes, and they form a cover for the saidreceivingchannel. The latter has an overflow socketpipe H, provided atany suitable place, but at such height relatively to the lower endsofthe exit-pipes F of the connecting units that the condensed acid whilecontinuously flowing into and out of the receiving-channel collects at ahigher level in this channel than the bottom of the said exit-pipes F,so as to form a liquid seal to prevent the uneondensed gases or vaporspassing' through the condensing' apparatus from coming into furthercontact with the condensed acid contained in the receiving-channel. Theconnecting units A B C, resting on the top flanges L of thereceiving-channel Gr, form a tightly-fitting cover therefor, asbestos,cement, or the like being applied between the body of the connectingunit A and the turned-up edge of the flanges L. The receiving-channel Gis also provided with an outlet O, which may be Vplaced at either end,as shown in Figs. l and 3, so that the acid contained in the saidreceiving-channel can at any desired time be run off into thecollecting' vessel P.

For the purpose of cooling or otherwise regulating the temperature ofthe acid flowing through the receiving-channel Gr, as below described,pipes of cylindrical or other form, such as M and N, may be arranged torun transversely through the receivingfchannel, admitting of freepassage of air when no attemperating vessel I is employed or when suchis used as hereinafter described, admitting Water or other attemperatingliquid, steam, or other warm gas to circulate freely.

In order to regulate the temperature in the interior of thereceiving-channel G, I some.- times employ an attemperating vessel I ofsuch form that there is room inside for the receiving-channel, itsflanges resting on the top of the said attemperating vessel I. I providethis attemperating vessel at suitable places with inlet and outletopenings for the introduction of an appropriate attemperating liquid orof steam, warm air, or other gas. In this manner I can control andregulate the temperature of the said flowing through thereceiving-channel G, and in this way the manufacture of Water-white acidis for the abovementioned reasons greatly facilitated.

In the modified construction of the apparatus shown in Fig. 4 theconnecting vessel is of D-section. In Fig. 5 the connecting vessel isshown as having flanges.

It is obvious that the form, size, and arrangement of the various partsof this condensing apparatus may be modified without departure from theessential features of the invention; also, that my improved condensingapparatus may be readily adapted for the condensation of products otherthan nitric acid.

I claim- In an acid-condenser, a connecting unit consisting of achamber, inlet and outlet socket unions thereon and a comparativelysmall depending outlet for condensed acid adapted to be liquid-sealed bythe condensed acid, substantially as described.

In testimony that I claim. the foregoing as my invention I have signedmy name in presence of two subscribing witnesses.

OSCAR GUTTMANN.

Witnessesz H. D. JAMESON, H. A. GREENGRAss.

IIO

